An integrative approach to healing ourselves and our world: honoring people, plants, planet

Posts tagged ‘Georgia native trees’

Sweetgum used to treat hypertension

In my assessment, the most undervalued native tree is the sweetgum. Due to its abundance – and to the sweetgum’s fruits, which look like miniature, medieval torture devices that litter the ground and clog lawnmowers – the sweetgum is condemned by many as a trash tree. Others might have a NIMBY response to sweetgums: they appreciate them along the highway, just not in their backyards.

Star-shaped sweetgum leaves turn a rainbow of colors in the fall, indicating its complex chemistry. Liquidambar, or sweetgum, is one of the sacred sources of Mayan copal resin.

A few features about sweetgums, though, point to this tree being more interesting than current conventional wisdom perceives.

During the fall, few trees offer the spectacular multi-hued, rainbow of color seen in the sweetgum’s star-shaped leaves. From shiny green, to yellow, to red, to deep eggplant-purple, sweetgum’s color spectrum appears to be indicative of its complex chemistry.

Within both common and botanical names of the sweetgum (Liquidambar styraciflua), we can gather that the tree offers a liquid, resinous, sweet-tasting gum. In the old days, the balsamic resin was called American styrax, or storax, and used as a natural chewing gum. The balsam resin is harvested by making a gash inside the inner bark so the liquid can ooze out. The balsam resin is medicinal, and further processing can produce tinctures and gums that also are medicinal.

Traditionally Native Americans used the resin and inner bark as an aid for wounds, sore throats, coughs and in treating infectious diarrhea. Chemical analysis has found astringent tannins and antimicrobial, anti-inflammatory compounds in sweetgum, which make it effective in treating skin and mucosal infections. The leaves also contain many of the medicinally active compounds.

Ethnobotanical research by the Foundation for Latin American Anthropological Research documents Liquidambar styraciflua, or arbol de estoraque, as one of the sacred sources of copal resin used for incense and burned during religious ceremonies. South Carolina Civil War surgeon and botanist writes that sweetgum incense was used in Mexico as an “excitant of the mucous system” and antimicrobial for infections of lungs, intestines and urinary tract.

Sweetgum balls look like miniature medieval torture devices.

Archeological research of pre-Columbian Aztecs discovered evidence of a large trade of Liquidambar for incense. “Trash tree” is clearly a perception.

Another traditional use by Cherokee Indians was to make a tea infusion of the inner bark as a sedative to calm the nerves.

Recent pharmaceutical research found that an alcohol extract of sweetgum reduced angiotensin II signaling, thereby reducing hypertension. The researchers isolated chemical constituents, benzyl benzoate and benzyl cinnamate, and discovered they served as antagonists for angiotensin II-induced hypertension. Will this trash tree be revalued as a native treasure?

Although sweetgums are prolific and long-lived, they are sensitive to urban sprawl and drought. According to a North Carolina State University study of sweetgums growing in the mid-Atlantic region of the United States, foliage is damaged from phytotoxic levels of troposheric ozone. We might regret that we didn’t appreciate the sweetgums while they were common.

In the Athens area, a walk around Memorial Park Lake offers a chance to take in the sweetgum’s beauty.

This article was originally published in the Urban Forager Column of the Athens Banner-Herald, Sunday, October 31, 2010.

Pawpaw used in cancer, head lice treatments

As for showy fall color, the Pawpaw isn’t glamorously breathtaking, but this time of year makes the yellowing of the leaves in mid-height understory an easy way to identify and stake-out Pawpaws in order to harvest their fruits the following summer.

The Common Pawpaw (Asimina triloba) and Smallflower Pawpaw (Asimina parviflora, Annonaceae family) are small trees or shrubs found in the mid-height understory of undisturbed soil. Large, pointed-tip, oval leaves with fishbone-like veins grow in an alternating pattern on rusty brown stems. Smallflower Pawpaw has smaller flowers and fruits and is shorter than Common Pawpaw. Smallflower also grows in drier soil than Common Pawpaw. For more images of Smallflower Pawpaw visit http://www.duke.edu/~cwcook/trees/aspa.html.

The Common Pawpaw (Asimina triloba, Annonaceae family) is a small tree or shrub found in rich, moist soil that has been undisturbed. Large, pointed-tip, oval leaves with fishbone-like veins grow in an alternating pattern on rusty brown stems. The stem and leaves, when broken, give off a slightly unpleasant odor, which tree expert Dr. Michael Dirr describes as “fetid.”

Cup-like, six-petaled flowers bloom in the spring. These inconspicuous, dark-burgundy beauties, are indicative of the unknown delicacy awaiting the forager-in-the-know come summer.

In early North American history, the Pawpaw fruit was common and widely known.

Nineteenth century medical botanists reported that African-Americans and Native Americans relished the custardy Pawpaw fruit for its taste, and also for its reported sedative and laxative effect.

Ethnobotanical accounts of Native Americans document various nations preparing mashed, fresh Pawpaws into cakes and then drying them for storage. The dried fruit was taken on hunting expeditions as dried fruit leather, or was soaked in warm water to either prepare as a sauce or to add to a corn meal mixture.

Pawpaws generally fall from the tree before they ripen. The forager gathers the fallen fruits, and ripens them outside because – at risk of losing some readers who were otherwise interested – I must disclaim, their smell is overpowering indoors. When the fruits turn from pale green to tamarind-brown, they’re ripe. The exterior is a fairly-tough peel, but the inside is soft and delicate like bananas.

The fruit has attractive, dark, reddish seeds with hard, shiny seedcoats. Be careful to remove the large seeds before eating Pawpaws because they’re considered to be a vermifuge (kills vermin or parasites), which means they’re toxic by most accounts. Powdered seeds, for example, were applied to a child’s head for lice control.

The destruction of habitat has drastically limited the quantity of Pawpaw fruit available. Local food and native plant enthusiasts are bringing back Pawpaw fruit through planting and providing the fruits at local markets. Pawpaws don’t tolerate the jostling required for grocery stores, so Pawpaw farmers must sell the fruits directly to customers as they ripen.

Pawpaw twigs are a source of annonaceous acetogenins, which have been used as an alternative treatment for certain cancers. Recent laboratory research at Purdue University’s School of Pharmacy and Pharmaceutical Science found that extracts of Pawpaw are “among the most potent of the 3,500 species of higher plants screened for bioactive compounds,” and proven to be an effective antitumor compound, as well as a treatment for oral herpes, and a pesticidal shampoo for head lice, fleas and ticks, already known in folk medicine.

Pawpaws make a case for protecting undisturbed forests as a source of economic and medicinal resources. The curious fruit also presents an argument for learning traditional medicine.

This article was originally published in the Urban Forager Column of the Athens Banner-Herald, October 24, 2010.

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